JP7424093B2 - Devices for printing 3D objects, methods for printing 3D objects - Google Patents

Description

The present invention relates to an apparatus for modeling a three-dimensional object and a method for modeling a three- dimensional object.

Generally speaking, equipment for printing three-dimensional objects (three-dimensional objects) uses techniques such as fused deposition (FDM), stereolithography, powder sintering, material lamination, powder fixation, sheet lamination, and directed energy deposition. Additive manufacturing methods using .

Also known is a method in which a light-absorbing three-dimensional shaping agent is irradiated with an optical vortex laser beam to cause the three-dimensional shaping agent to fly and three-dimensionally adhere to an object (Patent Document 1).

Re-table 2016-136722

However, in the configuration disclosed in Patent Document 1, the three-dimensional modeling agent is hardened by ultraviolet rays after adhering, so when the three-dimensional modeling agent collides with the object, it may cause damage, especially at the edges of the object. There is a problem in that the colliding three-dimensional modeling agent scatters, making it difficult to obtain good modeling quality.

The present invention has been made in view of the above problems, and an object of the present invention is to improve the quality of modeling.

In order to solve the above problems, an apparatus for modeling a three-dimensional object according to claim 1 of the present invention includes:
a carrier that carries a modeling material;
a means for imparting energy to the surface of the object;
means for causing the modeling material carried by the carrier to fly toward the surface of the shaped object to which the energy has been applied ,
The temperature of the surface of the modeled object is equal to or higher than the glass transition temperature when the model material reaches it.
The structure is as follows.

According to the present invention, modeling quality can be improved.

FIG. 1 is an explanatory diagram of an apparatus for modeling a three-dimensional object according to a first embodiment of the present invention. It is a micrograph of an example of the appearance of the modeling material on the carrier. This is a micrograph of another example. FIG. 3 is an explanatory diagram showing a cross-sectional observation state using a high-speed camera to explain the flying state of the modeling material. FIG. 3 is an explanatory diagram illustrating a falling trajectory of a modeling material. FIG. 3 is an explanatory diagram illustrating variation in landing of modeling material. FIG. 2 is a flowchart for explaining the operation of the embodiment. FIG. 3 is an explanatory diagram of an apparatus for modeling a three-dimensional object according to a second embodiment of the present invention. FIG. 7 is an explanatory diagram of an apparatus for modeling a three-dimensional object according to a third embodiment of the present invention. FIG. 7 is an explanatory diagram of an apparatus for modeling a three-dimensional object according to a fourth embodiment of the present invention. It is an explanatory view of the multi-air nozzle of the same device. FIG. 7 is an explanatory diagram of an apparatus for modeling a three-dimensional object according to a fifth embodiment of the present invention. FIG. 3 is an explanatory diagram illustrating a support method when modeling a complex shape. It is an explanatory view provided for explanation of the surface temperature of a three-dimensional object being modeled in an apparatus for modeling a three-dimensional structure according to a sixth embodiment of the present invention. It is an explanatory view showing the relationship between the flying modeling material and the irradiation area of the melting laser (laser light area). It is an explanatory view provided for explanation of the surface temperature of a three-dimensional object being modeled in an apparatus for modeling a three-dimensional structure according to a seventh embodiment of the present invention. It is an explanatory view provided for explanation of the device which makes particles fly concerning an 8th embodiment of the present invention. It is an explanatory diagram similarly provided for explanation of a fluence threshold. FIG. 7 is an explanatory diagram of an apparatus for modeling a three-dimensional object according to a ninth embodiment of the present invention.

Embodiments of the present invention will be described below with reference to the accompanying drawings. A first embodiment of the present invention will be described with reference to FIG. FIG. 1 is an explanatory diagram of an apparatus for modeling a three-dimensional object according to the same embodiment.

An apparatus 100 for modeling this three-dimensional object (referred to as a three-dimensional object modeling apparatus) includes a stage 101 that is a support member that supports an object to be formed (a object in the process of modeling) 200. The stage 101 is movable back and forth in the direction of arrow Y, and vertically movable in the direction of arrow Z, for example, at a pitch of 0.05 mm for the modeling thickness.

A stage heater 102 is arranged below the stage 101, and the temperature of the stage 101 is controlled to match the temperature of the modeling material 201. Further, a heat insulating plate 301 is arranged above the stage 101, and a model heater 302 is arranged on the lower surface of the heat insulating board 301. Energy is applied from the model heater 302, and the model 200 is heated to a temperature matching the modeling material 201. controlled by. Note that the shaped object heater 302 may be integrated with the heat insulating plate 301.

A carrier 111 made of a rotating member that supports particulate modeling material 201 is arranged above the stage 101 . The carrier 111 is constituted by a rotating drum that supports the modeling material 201 and rotates in the direction of the arrow (transfer direction), and transports the modeling material 201 to above the object 200 on the stage 101. The carrier 111 is a transparent member, and is made of a cylindrical glass member, but is not limited to this.

The modeling material 201 should be selected appropriately depending on the intended model 200, but in the case of resin, for example, PA12 (polyamide 12), PBT (polybutylene terephthalate), PSU (polysulfone), PA66 ( Polyamide 66), PET (polyethylene terephthalate), LCP (liquid crystal polymer), PEEK (polyetheretherketone), POM (polyacetal), PSF (polysulfone), PA6 (polyamide 6), PPS (polyphenylene sulfide), etc. In addition, the modeling material 201 is not limited to crystalline resins, but also includes amorphous resins such as PC (polycarbonate), ABS (acrylonitrile butadiene styrene), PEI (polyetherimide), or crystalline and amorphous resins. It may be a mixed resin.

Further, as the modeling material 201, various materials such as metal, ceramic, liquid, etc. can be used in addition to resin. Further, the modeling material 201 may be a material having a viscosity of 1 pa·s or more.

In this embodiment, the modeling material 201 is supported by the peripheral surface of the carrier 111 mainly by van der Waals force. Further, when the resistance value of the modeling material 201 is high, it can be supported only by electrostatic adhesion force.

A supply means 112 that supplies the modeling material 201 to the peripheral surface (surface) of the carrier 111 is arranged around the carrier 111 .

The supply means 112 includes a mesh roller 121 into which the modeling material 201 is supplied and rotates in the direction of the arrow, and a blade 122 that rubs the modeling material 201 within the mesh roller 121. The supply means 112 uses a blade 122 to rub the modeling material 201 to break up the agglomerations, thereby allowing the modeling material 201 to pass through the mesh roller 121 and forming a thin layer of the modeling material 201 on the peripheral surface of the carrier 111 .

The opening of the mesh of the mesh roller 121 is preferably 20 to 30% larger than the average particle size of the modeling material 201. A braided metal wire can be used, but a flat mesh made by electroforming or the like is more preferable. Further, the contact method of the blade 122 may be a trailing method as shown in FIG. 1, a counter method, or the like, as appropriate. The openings of the mesh may become clogged with the modeling material 201, but this can be resolved by bringing a brush made of fibers thinner than the openings into contact with the mesh roller from the outer periphery.

Here, the state of the modeling material 201 on the carrier 111 will be explained with reference to FIGS. 2 and 3. 2 and 3 are optical micrographs of examples of different modeling materials provided for the same explanation.

In FIG. 2, a columnar modeling material 201 with a volume average particle diameter of 48 μm is used as the modeling material 201, and the modeling material 201 is supplied to the peripheral surface of the carrier 111 using a stainless steel mesh with an opening of 70 μm and a wire diameter of 50 μm. This is an optical microscopic photograph taken when this was done. In this example, it was confirmed that the modeling materials 201 were arranged uniformly as a whole with almost no overlap.

In FIG. 3(a), PA12smooth manufactured by Siterit (volume average particle diameter is 38 μm) is used as the modeling material 201, and a stainless steel mesh with an opening of 60 μm and a wire diameter of 50 μm is used to transfer the modeling material 201 to the carrier 111. It is an optical microscope photograph when it was supplied to the peripheral surface. Note that FIG. 3(b) is an enlarged photograph of FIG. 3(a). In this example as well, the modeling materials 201 have almost no overlap and are uniformly arranged as a whole. Note that this modeling material 201 has a unique shape as if three or four spherical particles were combined, but they are not aggregated or overlapped.

The supply by the supply means 112 is not limited to mesh rollers. For example, contact supply using a rotating body, non-contact supply, non-contact spraying from a mesh, fluidized immersion using powder airflow stirring, etc. are also possible.

Returning to FIG. 1, a flying laser 115 is arranged inside the carrier 111 as a means for flying the modeling material 201 from the peripheral surface of the carrier 111.

Here, "flying" means that the modeling material 201 moves from the carrier 111 to the stage 101 side without contact. Unlike transfer, since it can move without contact, the loss of the modeling material 201 is reduced. It is also possible to improve the modeling accuracy.

The flying laser 115 includes a pulsed laser, and irradiates the modeling material 201 with a pulsed laser beam 115a from inside the carrier 111.

Further, the flying laser 115 includes an optical scanning section such as a galvano mirror. The optical scanning section changes the irradiation position of the pulsed laser beam 115a in the X direction perpendicular to both the arrow Y direction and the arrow Z direction by changing the angle of the mirror that reflects the pulsed laser beam 115a. The flying laser 115 can selectively irradiate a predetermined position in the X direction with a pulsed laser beam 115a using an optical scanning section.

When the modeling material 201 receives the pulsed laser beam 115a, the adhesion force of the powder is released due to a force called radiation pressure, and the building material 201 falls downward due to gravity or the like. Laser Induced Forward Transfer (LIFT), which is described in the conventionally known US006025110A, is a non-contact transfer method using laser irradiation to transfer a foil-like or liquid material that is in close contact with a carrier, and locally heats the material. When the material is vaporized, it flies from the peripheral surface of the carrier 111 in the direction of the pulsed laser beam 115a.

In addition, although FIG. 1 and the like show an example in which the modeling material 201 flies in the direction of gravity relative to the stage 101, it is not necessarily necessary to maintain perpendicular (90°) to the stage 101, and the modeling material 201 may be flown as necessary. It may also be tilted at a desired angle with respect to the stage 101.

In this embodiment, although it cannot be said that the latter mechanism makes no contribution, there are the following reasons why the former mechanism is considered to be the main one.
1. The flying start energy is the same for black powder and transparent powder, which have a high absorption rate of laser light.
2. Even if the carrier is a transparent resin film, the transparent powder will fly.
3. The transparent resin film of the carrier does not deteriorate even after being irradiated with the pulsed laser many times up to 1000 times.

It is preferable that the gap distance between the carrier 111 and the shaped object 200 is maintained at 3 to 10 times the average particle diameter of the shaped material 201. Thereby, contact between the upper and lower modeling materials before and after the flight can be avoided, and dissipation due to the flight can be avoided.

Here, the flying state of the modeling material 201 will be explained with reference to FIG. 4. FIG. 4 is an explanatory diagram for explaining the same. FIGS. 4(b) and 4(c) show cross-sectional observation using a high-speed camera.

As shown in FIG. 4(a1), when the modeling material 201 is stacked in multiple layers on the peripheral surface of the carrier 111, by irradiating the pulsed laser beam 115a, as shown in FIG. 4(b), the modeling material 201 is 201 is dissipated by flight.

On the other hand, as shown in FIG. 4(a2), when the modeling material 201 is supported without overlapping on the peripheral surface of the carrier 111, by irradiating the pulsed laser beam 115a, the shape shown in FIG. As shown, the modeling material 201 flies in the vertical direction.

Next, the falling trajectory and landing variation of the modeling material will be explained with reference to FIGS. 5 and 6.

FIG. 5 shows the results of continuous interval photography of the falling trajectories of multiple powders (modeling materials) under the following conditions.

PA12 powder: average particle size 38μm
Laser wavelength: 532nm
Pulse width: 15ps
Peak power: 0.74MW
Number of beam overlaps: 1.3
Beam diameter: 40μm
Frequency: 6.6kHz
Scanning speed: 200mm/s
Shooting: 20kfps

Similar flight was confirmed using combinations of transparent PC, black PC, PE, and PBT powders, laser wavelength: 1064 nm, pulse width: 2 ns, 20 ns, etc. In particular, transparent PC has a high transmittance at both 532 nm and 1064 nm, and is hardly absorbed as heat, so it is presumed that the mechanism is different from that of conventional LIFT.

At that time, the landing variation at the 0.5 mm gap position of the planned modeling position is shown in a histogram in FIG.

As can be seen from this result, 76% of the particles landed within a range of ±50 μm, which is sufficient for modeling with an accuracy of ±100 μm. Since the final shape is determined by the positional accuracy of the melting laser, any small amount of powder that strays from the melted area is removed after modeling.

There are no particular limitations on the laser light source for the flight laser 115, and it is preferable to use one that can emit pulses from picoseconds to nanoseconds. Examples of solid-state lasers include YAG lasers and titanium sapphire lasers. Examples of gas lasers include argon lasers, helium neon lasers, and carbon dioxide lasers. Semiconductor lasers are also preferable because they are small. A fiber laser is the most suitable light source for commercializing the present invention because of its high peak energy and miniaturization.

The wavelength of the melting laser can be selected as appropriate, but it is preferably 300 nm or more and 11 μm or less because there are many options for the light source. In particular, when the modeling material 201 is a resin, the region around 2460 nm is a composite absorption band of CH and CC bonds that almost all resins have, and the absorption rate was 80% or more for various resins, including those containing carbon. . Further, the absorption rate is 65% or more in the wavelength range of 2300 nm to 2500 nm, and stable flight and melting energy can be provided even in this range. Similarly, the absorption band of CC bond near 3400 nm and its overtone near 1700 nm are also suitable.

Since normal glass has a high transmittance in this wavelength range, it is easy to combine it with a base material.
The pulse frequency of the laser can be appropriately selected in combination with the scanning speed of the laser. If the beam diameters determined by the combination of the two overlap a lot, the laser will also hit the powder (modeling material) after it flies, and the powder will easily scatter. This tendency is remarkable when the beam diameters overlap two or more times, and powder dissipation is small when the beam diameters overlap 1.2 to 1.7 times.

Further, inside the carrier 111, a melting laser 116 is arranged as a means for applying energy to the surface of the shaped object 200. The melting laser 116 does not need to actively use pulses, and a continuous wave laser is suitable.

The melting laser 116 heats the surface of the object 200 formed on the stage 101 to melt it. It is sufficient that the material is brought into a molten state by the energy of one or more means for applying energy, and in addition to laser heating, convection, lamp, induction heating, dielectric heating, etc. can be applied. Moreover, the "surface" at this time may be one layer formed once, or may be a plurality of layers such as two or three layers. Further, it may be a part of each layer or the entire layer. In other words, it is important that part of the outermost layer is included.

In FIG. 1, the laser beam 116a of the melting laser 116 is aimed at the irradiation position (the landing position of the modeling material 201) of the pulsed laser beam 115a of the flying laser 115. The positions of both can be adjusted, and it is also possible to switch the adjustment positions depending on the material type, molding speed, etc.

As a result, the modeling material 201 that is ejected by the flying laser 115 lands on the surface of the object 200 that has been melted by the laser beam 116a of the melting laser 116 and is attached to the object 200.

Note that the timing of the flying of the modeling material 201 and the start timing of melting of the modeled object 200 is not particularly limited. In other words, the surface of the object 200 may be melted before the object 201 flies. Alternatively, after the modeling material 201 flies, the surface of the modeling object 200 may be melted, and the flying modeling material 201 may land on the melted surface.

The dispersion and excess/deficiency of the landing positions can be adjusted between laminated layers, and the flying laser 115 may differ from the shape of the model.It is the melting laser 116 that determines the shape of the model.

Further, a cleaning blade 117 for removing the modeling material 201 remaining on the carrier 111 is provided around the carrier 111 on the downstream side in the rotational direction of the carrier 111 than the area where the object 200 is to be modeled. The modeling material 201 scraped off by the cleaning blade 117 is collected into a collection case 118.

Next, the operation of this three-dimensional modeling apparatus 100 will be explained with reference to the flowchart of FIG. 7.

When the modeling operation is started, the supply means 112 rubs the modeling material 201 in the mesh roller 121 with the blade 122 (Step S1, hereinafter simply referred to as "S1"), and the modeling material 201 is placed in the mesh. (S2), and the modeling material 201 is placed on the circumferential surface of the carrier 111 in a non-overlapping state (S3). The supply means 112 continues to supply the carrier 111 until the modeling is completed (S4).

In this way, the modeling material 201 is supplied to the peripheral surface of the carrier 111 by the supply means 112, and the modeling material 201 is supported on the surface of the carrier 111 arranged above the stage 101 that supports the modeled object 200. .

Then, as the carrier 111 rotates, it is transferred above the stage 101, and a ceiling of the modeling material 201 is formed above the stage 101.

On the other hand, when the modeling start timing comes (S5), the laser beam 116a is irradiated from the melting laser 116 to heat and melt the part of the surface of the model 200 to which the modeling material 201 is attached (S6). However, only in the first layer at the start of modeling, the modeling material 201 is fused due to the temperature of the stage heater 102.

Then, a pulsed laser beam 115a is irradiated from the flying laser 115 to the required modeling material 201 according to the modeling data, and the modeling material 201 supported on the carrier 111 is caused to fly toward the melted part of the object 200. (S7).

The modeling material 201 flying from the carrier 111 lands on the surface of the molten object 200 and becomes integrated with the object 200, and the object 200 grows by at least one amount of modeling material.

In this way, while the modeling material 201 is sequentially transferred onto the stage 101 by the continuous rotation of the carrier 111, the melting laser 116 melts the modeling material 201 on the surface of the object 200, and the flying laser 115 causes the modeling material 201 to fly and land. The steps are repeated until the modeling is completed (S8).

Thereby, it is possible to grow the object 200 to a desired shape and form a three-dimensional object.

At this time, the flying modeling material 201 lands and adheres to the surface of the molten object 200 and is not dispersed due to collision, so high accuracy can be obtained even at the edges of the object 200, improving the quality of modeling. do.

In addition, as described above, not only crystalline resins but also mixed resins of crystalline and non-crystalline resins can be used as the powder, ensuring a diversity of materials, and making continuous molding possible. The molding speed can be increased, and the amount of waste material can be reduced.

Next, a second embodiment of the present invention will be described with reference to FIG. 8. FIG. 8 is an explanatory diagram of an apparatus for modeling a three-dimensional object according to the same embodiment.

In this embodiment, the liquid 130 is discharged onto the modeling material 201 around the carrier 111 of the first embodiment, between the supply means 112 and the position (modeling position) where the modeling material 201 is flown. A head 131 is arranged to apply the material.

On the downstream side of the head 131 in the powder transfer direction (rotation direction of the carrier 111), a suction means 132 is arranged to suck and collect the modeling material 201 to which the liquid 130 has not been applied. Further, a tank 133 for storing the modeling material 201 collected by the suction means 132 is provided.

In this way, by applying the liquid 130 to the modeling material 201 by the head 131, a liquid bridging force is generated between the modeling materials 201 and between the carrier 111 and the modeling material 201, so that the modeling material 201 can be applied more stably. It can be carried on the peripheral surface of the carrier 111 and transported to a modeling position.

At this time, by driving the head 131 according to the modeling data and selecting an area to apply the liquid 130, it is possible to form an image of the modeling material 201 on the carrier 111 according to the modeling data. Further, by adding a coloring material or an additive to the liquid discharged from the head 131, it is possible to add color or provide a function. Further, by using a multicolor head as the head 131, it is also possible to color the image in a desired color.

Note that if image formation with the modeling material 201 is not performed and a liquid bridging force is applied to the entire material, more stable transport to the modeling position can be achieved by spraying mist from an ultrasonic humidifier. .

Further, when the Van der Waals force or the resistance value of the powder is high, it is possible to transport the powder to the flying part using only electrostatic adhesion force.

The suction means 132 suctions and removes the modeling material 201 that is not supported on the surface of the carrier 111 by the liquid bridging force. In addition to vacuum suction, the suction means 132 is capable of electrostatic suction for materials other than highly conductive powder, and these can also be used in combination. Since the suctioned modeling material 201 does not have any liquid attached to it, it can also be resupplied into the supply means 112.

Here, the liquid 130 will be explained. Water is used as the liquid 130. In order to adjust the viscosity, a trace amount of thickener such as glycerin or polyethylene glycol may be included.

However, depending on the resin that constitutes the modeling material 201, it is necessary to avoid even trace amounts of water from hydrolysis, etc. In that case, use a liquid that is flame retardant and has no effect on the material, such as hydrogen fluoride. You can choose the type of solvent. For example, Fluorinert (registered trademark) manufactured by 3M and Galden (registered trademark) manufactured by Solvay can be selected depending on the boiling point. When a hydrogen fluoride solvent is decomposed by laser heating or the like, an absorbent such as calcium carbonate that absorbs hydrofluoric acid may be placed in the exhaust path.

Next, a third embodiment of the present invention will be described with reference to FIG. 9. FIG. 9 is an explanatory diagram of an apparatus for modeling a three-dimensional object according to the same embodiment.

In this embodiment, the carrier 111 is constituted by an endless belt that is a rotating member that moves around. For example, a nickel belt is used as the carrier 111.

The carrier 111 is wound around rollers 151, 152 and a heating roller 153 which is a heating means. Here, the heating roller 153 is arranged above the stage 101 at a position where the object 200 is formed (a printing position).

A backup roller 154 is arranged behind the heating roller 153. The backup roller 154 reduces the deflection of the endless belt caused by the small diameter of the heating roller 153.

The collection roller 134 is a bias roller, and uses a bias electric field to collect the modeling material 201 and drop it into the tank 133.

In this embodiment, the heating roller 153 is heated to, for example, 150° C., and the temperature at the contact portion between the carrier 111 and the heating roller 153 exceeds 100° C., and the building material 201 supported on the carrier 111 is cross-linked by water. Force is released (bumping). Further, the heating roller 153 has a relatively small diameter, and the crosslinking force of the modeling material 201 is released even by centrifugal force. As a result, the modeling material 201 flies from the carrier 111 toward the modeled object 200 at a moving speed of the carrier 111 of 300 mm/s, for example.

That is, in this embodiment, the means for making the modeling material 201 fly from the carrier 111 is composed of the heating roller 153 and the means for rotating the carrier 111, and the modeling material 201 is ejected from the circumferential surface of the carrier 111 by bumping and centrifugal force. Fly 201. More specifically, the inertial force accompanying the movement of the carrier 111 also acts, and the landing position is beyond the direction of movement of the carrier than directly below the flying position.

On the other hand, similarly to the first embodiment, the portion of the object 200 to which the modeling material 201 is attached is melted by the melting laser 116.

As a result, the modeling material 201 flying from the carrier 111 adheres to the melted part of the modeling object 200, and the modeling material 200 grows.

Next, a fourth embodiment of the present invention will be described with reference to FIGS. 10 and 11. FIG. 10 is an explanatory diagram of an apparatus for modeling a three-dimensional object according to the same embodiment, and FIG. 11 is an explanatory diagram of a multi-air nozzle of the same apparatus.

In this embodiment, the carrier 111 is composed of an endless mesh belt.

The carrier 111 is wound around rollers 151 and 152 and rollers 156 and 157. A multi-air nozzle 160 is disposed between the rollers 156 and 157 and above the stage 101 at a position where the object 200 is formed (a printing position).

Air is sent to the multi-air nozzle 160 from a supply source, and air is blown out from the nozzle 160a toward the carrier 111 made of a mesh belt, and the modeling material 201 is flown from the carrier 111 by this air pressure.

Although an inkjet was used to form a powder image before flying, it is also possible to remove the negative portion using a laser as in other embodiments. Further, in the case of an inkjet-like configuration in which the multi-air nozzle itself has a microcavity structure and can be individually controlled, there is no need for prior image formation, and a powderjet configuration can also be implemented.

On the other hand, similarly to the first embodiment, the portion of the object 200 to which the modeling material 201 is attached is heated and melted by the melting laser 116.

As a result, the modeling material 201 flying from the carrier 111 adheres to the melted portion of the modeled object 200, and the modeled object 200 grows.

Next, a fifth embodiment of the present invention will be described with reference to FIG. 12. FIG. 12 is an explanatory diagram of an apparatus for modeling a three-dimensional object according to the same embodiment.

In this embodiment, the carrier 111 is constituted by an endless belt that is a rotating member that moves around. The carrier 111 is made of, for example, a PET film (Lumirror manufactured by Toray Industries, Ltd.). It can also be made of polyimide film (Kapton H manufactured by Toray Industries). These films are industrially mass-produced and can be used as endless belts, but it is also possible to use long film rolls as they are and use them repeatedly in a roll-to-roll manner.

The carrier 111 is wound around rollers 151 and 152 and a fixing member 155. Here, the fixing member 155 is arranged above the stage 101 at a position where the object 200 is to be modeled (modeling position).

A knurled roller is used as the supply roller 123 of the supply means 112, and an abutment roller 124 having a rubber layer on the surface is arranged opposite to the supply roller 123.

The pulsed laser beam 115a of the flying laser 115 has an incident angle of 20 degrees, and is configured so that it can be irradiated onto the carrier 11 through the slit portion 155a of the fixing member 155.

Further, a coating device 163 for discharging and coating a coating liquid is arranged. The coating device 163 discharges a heat-resistant, water-soluble liquid 162, such as magnesium sulfate, which is precipitated by heating, for example. This is intended to improve the ability to remove supports at the interface of the modeled object 200. In addition to the low viscosity liquid, the coating liquid may be in the form of a slurry or a resin heated and melted.

Next, a support method when modeling a complex shape will be described with reference to FIG. 13.

Here, as shown in FIG. 13(a), a U-shaped object 200 is formed. At this time, as shown in FIG. 13(b), a support material 211 is used that supports the upper part of the object 200 and can be easily removed after modeling.

When forming the support portion using the support material 211, only the flying laser 115 is operated and the melting laser 116 is not operated. The height of the powder can be adjusted by the flight frequency, and can be predicted and set in advance in the modeling data, or can be corrected while measuring the shape during modeling.

Furthermore, as shown in FIGS. 13(c) and 13(d), in consideration of the possibility that the support material 201b will collapse and the accuracy, the objects 212 to 214 are formed on a part of the support material 211 and removed after the formation. .

Next, a sixth embodiment of the present invention will be described with reference to FIG. 14. FIG. 14 is an explanatory diagram illustrating the surface temperature of a three-dimensional object being formed in the apparatus for forming a three-dimensional object according to the same embodiment.

The device configuration and modeling operation in this embodiment are the same as those in the first embodiment. Note that the device configurations in the second to fifth embodiments may also be used.

In this embodiment, PEEK, which is a crystalline resin, is used as the modeling material 201 (material of the modeled object 200). Other crystalline resins can also be used.

FIG. 14 shows the change in surface temperature of the object 200 over time after the start of modeling. S6 in FIG. 14 indicates the timing of step S6 (melting laser irradiation) and step S7 (flying laser irradiation) in FIG. 7.

In this embodiment, as shown in FIG. 14, the surface of the object 200, whose temperature has increased due to the irradiation of the laser beam 116a by the melting laser 116 in step S7, is covered with the object 201 that is flown by the flying laser 115. When they reach (collide) and are laminated, the glass transition temperature Tg is maintained at 143° C. or higher.

By making the temperature of the surface of the modeled object 200 higher than the glass transition temperature Tg, the surface of the modeled object 200 becomes rubbery, and when the flying modeling material 201 collides with the modeled object 200, the surface of the modeled object 200 is deformed. However, the kinetic energy of the modeling material 201 can be absorbed.

On the other hand, if the temperature of the surface of the object 200 is lower than the glass transition temperature Tg, the surface of the object 200 will not be sufficiently deformed when the flying object 201 collides with the object 200. This is not preferable because the kinetic energy of the modeling material 201 cannot be sufficiently absorbed.

As a result, when the building material 201 collides with (reaches) the surface of the object 200, the object 200 is less likely to bounce back, and the scattering of the object 201 can be suppressed, improving the dimensional accuracy and surface quality of the object 200. This results in improved printing quality.

In this case, the temperature of the surface of the modeled object 200 is preferably a crystallization temperature (Tc) of 300° C. or higher when PEEK is used as the model material 201. Thereby, it is possible to suppress the local occurrence of warpage due to rapid contraction accompanying crystallization when the temperature falls, and to obtain a three-dimensional molded object with a stable shape.

In order to maintain the surface temperature of the object 200, as shown in FIG. 1, a object heater 302 serving as a means for applying energy to the object 200 is arranged above the stage 101. The object heating heater 302 is formed of a planar resistance heating element, and maintains the ambient temperature around the object 200 at 143° C. or higher, which is the glass transition temperature Tg of the building material 201.

Further, air is blown between the heat insulating plate 301 and the stage 101 by a fan or the like, so that the temperature of the atmosphere is made uniform.

It is also possible to arrange a temperature sensor around the shaped object heater 302 or the shaped object 200 and perform temperature control so as to keep the temperature of the atmosphere around the shaped object 200 constant. By keeping the ambient temperature high, not only can scattering of the building material 201 when it collides with the object 200 can be suppressed, but also warping can be suppressed by reducing the temperature gradient inside the object 200 after it has been formed. You can also do it.

The object heating heater 302 controls the atmosphere around the object 200 so that the temperature of the object 201 before flying (in a supported state) by the flying laser 115 is maintained at 143° C. or higher, which is the glass transition temperature Tg. Heating temperature.

Thereby, the energy input by the melting laser 116 can be reduced, and speeding up and power saving can be achieved.

On the other hand, the temperature of the modeling material 201 before being ejected by the ejecting laser 115 may be lower than the glass transition temperature Tg of 143° C., and by preventing the material 201 from becoming a rubber state, the adhesive force with the carrier 111 can be improved. It is preferable to keep it below a certain level and adjust it so that the modeling material 201 can easily fly.

Further, as shown in FIG. 14, in step 6, the temperature of the surface of the modeled object 200 is less than 343° C., which is the melting point Tm, before irradiation with the laser beam 116a by the melting laser 116, and After irradiation, the temperature was 343°C or higher.

By irradiating the laser beam 116a with the melting laser 116 so that the temperature is higher than the melting point Tm, the modeled object 200 becomes a liquid state, and the molten modeling materials 201 are bonded together to form a high-strength modeled object. can do. If the temperature remains below the melting point Tm even after irradiation, the modeling material 201 cannot be sufficiently bonded to the modeling object 200.

On the other hand, by setting the temperature to be less than the melting point Tm before irradiating the laser beam 116a with the melting laser 116, the entire modeled object 200 is prevented from melting and collapsing, and a certain dimensional accuracy is maintained. be able to.

Note that the temperature increase on the surface of the object 200 caused by the melting laser 116 is set to 50° C., which is a temperature increase that does not cause warping due to local deformation of the object.

Further, although the shaped object heater 302 is used as a means for applying energy (maintaining) the temperature of the surface of the shaped object 200 to a temperature higher than the glass transition temperature Tg, the present invention is not limited to this.

For example, the output and irradiation time of the melting laser 116, or the time interval between irradiation of the laser beam 116a from the melting laser 116 and the laser beam 115a from the flight laser 115, etc. can be adjusted by controlling the laser. .

For example, when adjusting the time interval, the laser beam 116a from the melting laser 116 is irradiated onto the surface of the object 200, and after the surface temperature of the object 200 exceeds the melting point, the heat is transferred to the object 200. The time interval may be determined within a range in which the temperature does not fall below the glass transition temperature Tg during the process in which the temperature is reduced by being transmitted to the interior or the atmosphere.

Next, the time interval for flying the modeling material will be explained.

When the building material 201 flies and collides with the surface of the object 200, heat is transferred from the object 200 and the temperature of the object 201 increases. If the heat transfer at this time is insufficient, the surface temperature of the building material 201 will not rise sufficiently when the next building material 201 collides with the same position, and there is a possibility that the glass transition temperature Tg will not be reached.

Therefore, in order to obtain sufficient heat transfer time, when the average particle size of the modeling material 201 is L [μm], after the modeling material 201 flies and reaches the surface of the modeled object 200, The time interval from when the modeling material 201 flies to a position until it reaches the surface of the modeled object 200 is set to be equal to or larger than L×L/200 [ms]. If the time interval is less than L×L/200 [ms], it is not preferable because the heat of the particles reaching the surface is not sufficiently diffused and the entire particles are not melted.

The threshold value of the time interval is L ² /α, which is the threshold value for making the temperature of a material with thickness L and thermal diffusivity α uniform (corresponding to the time constant RC in an RC circuit), and for resin materials, generally α=2. This was derived using the fact that the velocity is 0×10 ⁻⁷ [m ² /s]. When L=50 [μm], the time interval is required to be 12.5 [ms] or more, so for example, the time interval at which the modeling material 201 is made to fly is set to 20 [ms].

Thereby, when the modeling material 201 flies and collides with the surface of the object 200, sufficient time can be secured for heat to be transmitted from the object 200 and the temperature of the object 201 to rise, improving the quality of the object.

Here, specific examples will be described with reference to Table 1.

<Example 1-1 to Example 1-6>
As shown in Table 1, the resins (modeling material 201) include PEEK (Examples 1-1 and 1-2), PA12 (Examples 1-3 and 1-4), and PBT (Examples 1-5 and 1-4). 6) was used. Then, the surface temperature of the shaped object 200 before heating is set to a temperature below the melting point, and the surface temperature at which the resin reaches after heating (achieved surface temperature) is equal to or higher than the glass transition temperature Tg (Examples 1-1, 1-3 , 1-5) or above the crystallization temperature Tc (Examples 1-2, 1-4, 1-6). Further, the time interval for making the resin fly was set to 0.1 s, which was equal to or more than "L×L/200 [ms]" in both cases.

Note that the ambient temperature was 25° C. in all cases. Further, the temperature was measured using Keyence Corporation's product name FT-H20. Further, the time interval was measured using Keyence Corporation's product name NR-500.

The melting state of Examples 1-1 to 1-6 was evaluated, and the evaluation results are shown in Table 1. An evaluation result of “〇” indicates that the modeling material has melted and the modeling material has bonded to the object.

Next, heating of the modeling material during flight will be explained with reference to FIG. 15 as well. FIG. 15 is an explanatory diagram showing the relationship between the flying modeling material and the irradiation area of the melting laser (laser beam area).

The laser beam 116a is irradiated onto the surface of the object 200 and passes above the object 200 by being incident obliquely.

Here, while the laser beam 116a is irradiated from the melting laser 116, the modeling material 201 flies and lands on the surface of the modeled object 200.

In this way, by directly irradiating the flying modeling material 201 with the laser beam 116a of the melting laser 116, not only the surface of the modeling object 200 but also the modeling material 201 can be heated at the same time.

Therefore, if the landing material 201 itself becomes higher than the glass transition temperature Tg, or if the temperature at the time of collision with the object 200 increases, the surface of the object 200 will be more heated when it collides with the object 200. Deforms and absorbs kinetic energy.

This makes it difficult for the building material 201 to bounce back when it collides with the surface of the object 200, suppressing the scattering of the object 201, and further improving the dimensional accuracy and surface quality of the object 200, thereby improving the quality of the object. be able to.

Next, a seventh embodiment of the present invention will be described with reference to FIG. 16. FIG. 16 is an explanatory diagram for explaining the surface temperature of a three-dimensional object being formed in the apparatus for forming a three-dimensional object according to the same embodiment.

The device configuration and modeling operation in this embodiment are the same as those in the first embodiment. Note that the device configurations in the second to fifth embodiments may also be used.

In this embodiment, PES, which is an amorphous resin, is used as the modeling material 201. Other amorphous resins can also be used.

When the modeling material 201 is an amorphous resin, it does not have a melting point, so when trying to obtain the same effect as in the sixth embodiment, the temperature of the surface of the modeled object 200 before and after irradiation with the melting laser 116 is cannot be specified.

Therefore, in this embodiment, the conditions are defined based on the viscosity of the resin.

The viscosity of the resin is 1.0×10 ³ Pa·s or more before being irradiated with the laser beam 116a from the melting laser 116, whereas it is 1.0×10 ³ Pa·s after being irradiated with the laser beam 116a. It should be less than s. In other words, after the surface of the modeled object 200 is heated by means for applying energy, the viscosity becomes less than 1.0×10 ³ Pa·s, and the viscosity before heating is 1.0×10 ³ Pa·s or more. The configuration is as follows.

Here, specific examples will be described with reference to Table 2.

<Example 2-1>
PES was used as the resin (modeling material 201), and the temperature was 250° C. before irradiation with laser light and 360° C. after irradiation. At this time, the viscosity before irradiation was 3.0×10 ³ Pa·s, and after irradiation was 6.0×10 ² Pa·s.

<Example 2-2>
PVC was used as the resin (modeling material 201), and the temperature was 50° C. before applying laser light energy and 150° C. after applying it. At this time, the viscosity before irradiation was 4.0×10 ³ Pa・s, and after irradiation was 5.0×10 ² Pa・

The temperature was measured using Keyence Corporation's product name FT-H20. Further, the viscosity was measured according to JIS8803:2011.

The melting state of Examples 2-1 and 2-2 was evaluated, and the evaluation results are shown in Table 2. The symbol “〇” in the evaluation results indicates that the modeling material has melted and the modeling material has bonded to the modeling object.

As a result, even for an amorphous resin that does not have a melting point, the shaped object 200 becomes soft and the powders bond together after being irradiated with the laser beam 116a from the melting laser 116, similarly to the sixth embodiment. This makes it possible to form objects with high strength. By making the temperature lower than the melting point before irradiation with the laser light from the melting laser 116, it is possible to prevent the entire shaped object 200 from becoming soft and collapsing, and to maintain a certain dimensional accuracy.

In each of the embodiments described above, since the layers are laminated without contact, most of the problems that occur in the STEP method of electrophotography can be solved. For example, in the method of laminating molten resin by bringing it into contact with the modeled object, offset and roughness easily occur at the interface, and there are material limitations such as strict control of temperature, increased time, and melt viscosity. Although there is a problem that conductive resin cannot be used because of the use of conductive resins, these problems can be overcome by laminating them without contact.

Next, an eighth embodiment of the present invention will be described with reference to FIG. 17. FIG. 17 is an explanatory diagram for explaining the device for flying particles according to the same embodiment.

In this embodiment, an example will be described in which a device for making particles fly is applied to the device for modeling a three-dimensional object according to the first embodiment.

As shown in FIG. 17, when the modeling material 201, which is a particle, is held on one surface of the carrier 111 with an adsorption force Fv, the surface of the carrier 111 opposite to the surface on which the modeling material 201 is held is A flying laser 115 is provided as a means for irradiating a laser beam 115a.

The flight laser 115 irradiates laser light 115a with pulsed light having a pulse width of 10 μs or less. The pulse width may be 8 μs, 5 μs or less, or 2 μs. We have also confirmed that it is possible to achieve this even in nanoseconds or picoseconds. Irradiation with a pulse width longer than 10 μs is not preferable because thermal diffusion within the modeling material exceeds μm and force is not transmitted to the material.

Here, in FIG. 17, "Fg" represents the gravity applied to the modeling material 201 (particles). This is generally calculated by multiplying the weight, which is the product of the object's volume and density, by the gravitational acceleration. As the modeling material 201, the gravity Fg was determined to be about 10 ^-10 N when determined using the above-mentioned PA12smooth manufactured by Siterit (volume average particle size: 38 μm).

“Fvdw” represents the van der Waals force applied to the modeling material 201. This was calculated to be approximately 10 ⁻⁷ N.

“Fe” represents the adsorption force of the modeling material 201 due to electrostatic force. This is known to be a force on the order of 10 N for carrier materials in printers of similar size, but this depends on the amount of charge of the building material 201 (particles, powder).

The above is obtained by calculation, but the adhesion force Fv, which is the sum of Fvdw and Fe, can be obtained experimentally by an adhesion test using a centrifuge, etc., but it can also be obtained by an adhesion test using Siterit's PA12smooth. As a result, Fg was approximately 10 ⁻⁸ N.

Other factors constituting Fvdw include liquid bridging force that occurs when liquid is contained between the modeling material 201 (particles) and the carrier 111.

“Fr” represents the force applied to the modeling material 201 due to radiation pressure. Fr can be calculated by calculation, but when calculated with a pulse width of 10 ps and a pulse energy of 1 μJ, the instantaneous force was about 10 ⁻⁴ N.

"Fab" represents the force exerted on the modeling material 201 due to the momentary gasification of some solids on the surface of the modeling material 201 by laser ablation, which generates pressure when the gas is injected.

For example, when a laser with a pulse width of approximately ps is used, a phenomenon generally called ablation occurs in which this gas and, in some cases, turn into plasma. These are known to reach high temperatures of several hundred thousand degrees, and in that case, the injection pressure can be considered to be much larger than Fvdw.

Therefore, if the laser energy has enough energy to induce ablation, the force instantaneously applied to the modeling material 201 greatly exceeds the adhesion force.

Here, whether the laser exceeds the ablation threshold for the object is usually discussed based on whether the laser fluence Fll exceeds the threshold. The threshold at this time will be referred to as a "fluence threshold" hereinafter.

The fluence Fll is calculated by dividing the pulse energy J by the area of the laser (generally, the unit is J/cm ² ). In the case of powder materials, the fluence threshold value Flth is generally 0.1-1.0 J/cm ² . This can be calculated by irradiating the bulk material of the material with a laser.

This is a calculation formula when the laser beam is a general Gaussian beam, but of course, the value changes depending on the center position and the periphery of the beam, and it also applies to other irregular beams (donut beam, top hat beam) Then, we have to use a calculation formula that corresponds to that.

From these, the adsorption force Fvdw is composed of van der Waals force, electrostatic force, and liquid bridging force, and when the gravity acting on the particles (modeling material 201) is Fg, by setting Fv>Fg, the support 111 The modeling material 201 can be supported on the substrate.

In addition, the input conditions for the laser beam are such that, where Fr is the force applied to the particles (modeling material 201) by the radiation pressure, Fr > Fv - Fg in the vertical direction to the adsorption surface to make the particles fly. Can be done.

Here, specific examples will be described with reference to Table 3.

<Example 3-1 to Example 3-3>
PA12 (Example 3-1), PE (Example 3-2), and PC (Example 3-3) were used as resins, Fv>Fg, and the laser beam input conditions were Fr>Fv-Fg, And so.

The flight conditions of Examples 3-1 to 3-3 were confirmed. The results are shown in Table 1.

In addition, the laser beam input conditions are as follows: Fl<Flth1 and Fl<Flth2, where Flth1 is the fluence threshold of the powder, Flth2 is the fluence threshold of the carrier, and Fl is the fluence. let

At this time, it should be noted that there are multiple fluence thresholds. As shown in FIG. 18, when the carrier is composed of multiple layers, for example, when it has a sandwich structure of carrier 111A → carrier 111B → carrier 111A, the upper surface of one carrier 111A is The lower surface of the other carrier 111A is in the atmospheric environment 2.

In this case, the carrier 111A and the carrier 111B may be, for example, a base material and a thin film layer attached to the surface thereof, or a plurality of base materials may be laminated together. It is also conceivable that the surface shape is not flat but has an uneven shape. The atmospheric environment may include air, nitrogen, argon, etc., temperature, and humidity conditions.

It is known that the fluence threshold value differs depending on the material of the substance and the atmospheric environment, so in the case of FIG. B2, the interface B3 between the carrier 111A, and the atmospheric environment 2 are considered to have different fluence thresholds. Furthermore, the spot diameter of the laser beam is of course different, and the fluence threshold inside the carrier rather than at its boundary surface is also different.

Therefore, it is noted that the fluence conditions must be selected with all possible fluence thresholds depending on the laser conditions, taking into account these conditions.

By using the device for flying particles according to this embodiment, the particles (powder) to be flown are not limited. That is, as described above, particles (powder) of, for example, crystalline resin, amorphous resin, engineering plastic, metal material, ceramic, etc. can be flown.

If the particles can be adsorbed onto the carrier, a three-dimensional object can be formed.

Here, it is preferable that the carrier 111 and the stage 101 on which the three-dimensional object is modeled be configured to move in the same direction at opposing locations.

Further, it is preferable that the moving speed of the carrier is faster than the moving speed of the stage. Normally, it is difficult to completely fill the carrier 111 with powder material. Therefore, the carrier 111 needs to move at a faster speed in order to supply the powder to the three-dimensional structure 101 at a sufficient speed.

Next, a ninth embodiment of the present invention will be described with reference to FIG. 19. FIG. 19 is an explanatory diagram of an apparatus for modeling a three-dimensional object according to the same embodiment.

In this embodiment, the carrier 111 in the first embodiment is made of a film. The film as the carrier 111 is used while being wound up from the feed roll 111A to the take-up roll 111B.

Then, when the carrier 111 fed out from the feeding roll 111A is interrupted, the film serving as the carrier 111 is bonded and connected using the feeding roll 111C for replenishment. This allows modeling to continue in a short time.

In this embodiment, the laser beam 116a of the melting laser 116 is located a little far from the landing position of the modeling material 201, but can impart energy at an incident angle of 15 degrees.

The closer the incident angle is to 0 degrees, the less problems such as shadows caused by foreign objects or insufficiently melted parts will occur when molding a complex shape.

When the stage 101 moves in the Y1 direction, the surface of the modeled object 200 is melted and the material is landed. Furthermore, when the stage 101 moves in the Y2 direction, the powder (modeling material 201) that has landed on the surface softened above Tg is heated and melted.

100 Device for modeling three-dimensional objects 101 Stage (supporting member)
111 Carrier 112 Supply means 115 Flying laser (flying means)
116 Melting laser (means for applying energy)
200 Modeled object 201 Powder 201 Modeling material (particles)
301 Heat insulating board 302 Molded object heater (means for auxiliary energy application)

Claims (17)

a carrier that carries a modeling material;
a means for imparting energy to the surface of the object;
means for causing the modeling material carried by the carrier to fly toward the surface of the shaped object to which the energy has been applied,
An apparatus for modeling a three-dimensional object, characterized in that the temperature of the surface of the object is equal to or higher than the glass transition temperature when the object reaches the temperature of the object. a carrier that carries a modeling material;
a means for imparting energy to the surface of the object;
means for causing the modeling material carried by the carrier to fly toward the surface of the shaped object to which the energy has been applied,
The means for applying energy heats the surface of the model so that the temperature of the surface of the model becomes equal to or higher than the glass transition temperature when the model material reaches the surface of the model, and also applies heat to the surface of the model. An apparatus for modeling a three-dimensional object, characterized in that the flying modeling material is also heated before it reaches the surface of the object. a carrier that carries a modeling material;
a means for imparting energy to the surface of the object;
means for causing the modeling material carried by the carrier to fly toward the surface of the shaped object to which the energy has been applied,
An apparatus for forming a three-dimensional object, wherein the means for applying energy heats the ambient temperature around the object until the surface of the object reaches a glass transition temperature or higher. The device for modeling a three-dimensional object according to any one of claims 1 to 3, wherein the carrier is a rotating member. 5. The device for modeling a three-dimensional object according to claim 1, wherein the flying means is means for irradiating a pulsed laser. The three-dimensional modeling according to any one of claims 1 to 4, wherein the flying means includes a heating means for heating the circularly moving carrier and the modeling material supported on the carrier. A device that shapes things. 5. The apparatus for modeling a three-dimensional object according to claim 1, wherein the flying means is means for blowing air onto the modeling material supported on the carrier. 8. The apparatus for modeling a three-dimensional object according to claim 1, further comprising means for applying a liquid to the modeling material supported on the carrier. 9. The apparatus for modeling a three-dimensional object according to claim 8, further comprising means for removing the modeling material to which the liquid has not been applied from the carrier. Claim 1, wherein when the average particle size of the modeling material is L [μm], the time interval at which the modeling material reaches the surface of the modeling object is L×L/200 [ms] or more. 10. A device for modeling a three-dimensional object according to any one of items 1 to 9. The modeling material is a crystalline resin,
Modeling a three-dimensional model according to any one of claims 1 to 10, wherein the temperature of the surface of the model becomes equal to or higher than the melting point of the model material after being heated by the means for applying energy. Device. 12. The apparatus for modeling a three-dimensional object according to claim 11, wherein the temperature of the surface of the object is lower than the melting point of the modeling material before being heated by the means for applying energy . The modeling material is an amorphous resin,
The three-dimensional structure according to any one of claims 1 to 10, wherein the surface of the three-dimensional structure has a viscosity of less than 1.0×10 Pa·s after being heated by the means for applying energy. A device for modeling. 14. The device for modeling a three-dimensional object according to claim 13, wherein the surface of the object has a viscosity of 1.0 x 10<3> Pa·s or more before being heated by the means for applying energy. a step of supporting a modeling material on the surface of a carrier;
A process of applying energy to the surface of the modeled object,
a step of causing the modeling material carried by the carrier to fly onto the surface of the shaped object to which the energy has been applied;
A method for modeling a three-dimensional object, characterized in that the temperature of the surface of the object is made equal to or higher than the glass transition temperature when the building material reaches it. a step of supporting a modeling material on the surface of a carrier;
A process of applying energy to the surface of the modeled object,
a step of causing the modeling material carried by the carrier to fly onto the surface of the shaped object to which the energy has been applied;
When the modeling material reaches the surface of the modeling object, the temperature of the surface of the modeling object is heated to be equal to or higher than the glass transition temperature, and the modeling material flying toward the surface of the modeling object is A method for modeling a three-dimensional object, characterized in that the modeling material is also heated before reaching the surface of the object. a step of supporting a modeling material on the surface of a carrier;
A process of applying energy to the surface of the modeled object,
a step of causing the modeling material carried by the carrier to fly onto the surface of the shaped object to which the energy has been applied;
A method for forming a three-dimensional object, characterized in that the ambient temperature around the object is heated until the surface of the object reaches a glass transition temperature or higher.

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